"It's not my decision," he told reporters gathered at a weekly news conference, in response to an AFP question.

More than two months after being appointed premier, Abdel Mahdi has yet to fill eight of his cabinet's 22 posts, including the key ministers of interior and defence.

He has named candidates for the eight ministries, but parliament has repeatedly delayed a vote on them due to divisions among various factions.

The proposed names for interior and defence ministers, Faleh al-Fayyadh and Faysal al-Jarba respectively, have the support of political parties with close ties to Iran.

Abdel Mahdi has said that he named a share of the cabinet, but that the rest of the posts would be doled out according to arrangements among rival blocs.

"We were free to choose eight or nine ministers, and the rest are the results of political agreements," he said.

"When it comes to the interior and defence, these were the choices of the political blocs, not of the premier."

Parliament is expected to meet next week, but it is unclear if they will vote on the empty posts.

As the process drags on, observers have wondered whether Abdel Mahdi could resign, destabilising a country getting back on its feet one year after ousting the Islamic State group.

To mark that occasion on Monday, the government reopened a main route in Baghdad's high-security Green Zone to through traffic for five hours daily.

The area, home to Iraqi government buildings, United Nations agencies, and foreign embassies including the American mission, has been sealed off to most Iraqis since the 2003 US-led invasion.

Many Iraqis hope its reopening could signal better days.

"It carries an important message," Abdel Mahdi said Tuesday.

"There were fears from the diplomatic missions, who told us 'We don't want to risk it,'" he said.

"But this decision is irreversible. If there's no security on the outside, then there's no security for those inside either. The citizen should be just as protected as the official."